78 g of potassium (K)%C2%A0react with 71 g of chlorine (Cl) to produce potassium chloride. According to the Law of Conservation of Mass, what is the mass of the product (2KCl)?%C2%A0(1 point) Responses

Question

149 g

156 g

2 g

4 g

GPT 3.5 · Answer

The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. Therefore, the mass of the reactants must equal the mass of the products.

The molar mass of potassium (K) is 39.1 g/mol, and the molar mass of chlorine (Cl) is 35.5 g/mol.

To determine the mass of the product (2KCl), we need to calculate the mass of potassium chloride (KCl) formed.

The molar mass of potassium chloride (KCl) is 74.55 g/mol (39.1 g/mol + 35.5 g/mol).

To find the mass of the product (2KCl), we need to calculate the number of moles of potassium (K) and chlorine (Cl) using their given masses and their respective molar masses.

Number of moles of potassium (K) = mass of potassium (K) / molar mass of potassium (K)
= 78 g / 39.1 g/mol
= 1.995 moles

Number of moles of chlorine (Cl) = mass of chlorine (Cl) / molar mass of chlorine (Cl)
= 71 g / 35.5 g/mol
= 2 moles

According to the Law of Conservation of Mass, the moles of the reactants must be equal to the moles of the product.

In this case, since 2 moles of chlorine (Cl) react with 1.995 moles of potassium (K), we can conclude that the limiting reagent is potassium (K) because it is not completely consumed.

The number of moles of potassium chloride (KCl) formed will be half of the number of moles of the limiting reagent, which is 0.9975 moles (1.995 moles / 2).

Now, we can calculate the mass of the product (2KCl) using the mass of potassium chloride (KCl) and its molar mass.

Mass of potassium chloride (KCl) = moles of potassium chloride (KCl) x molar mass of potassium chloride (KCl)
= 0.9975 moles x 74.55 g/mol
= 74.24 g

Since 2KCl represents twice the molar mass of potassium chloride (KCl), the mass of the product (2KCl) will be twice the mass of potassium chloride (KCl).

Mass of the product (2KCl) = 2 x mass of potassium chloride (KCl)
= 2 x 74.24 g
= 148.48 g

Rounded to the nearest whole number, the mass of the product (2KCl) is 149 g.

Therefore, the correct answer is:

The mass of the product (2KCl) is 149 g.